This invention relates to a method of manufacturing a hybrid integrated circuit assembly which is formed by mounting electronic components on an electrically conductive mounting board.
In circuits disposed in high temperature environments, such as internal combustion engine ignition circuits or voltage control circuit for magnet type generators driven by internal combustion engines, the electronic components are mounted on a mounting board made of electrically conductive material such as copper or aluminum excellent in heat conductivity in order to improve the heat radiation.
Shown in FIG. 1 is a conventional hybrid integrated circuit assembly of this type, which forms a circuit as shown in FIG. 2. The hybrid integrated circuit assembly, as shown in FIG. 1, comprises: mounting boards 1' and 2'; diodes 3 and 4; and a thyristor 5. In a conventional method of manufacturing this hybrid integrated circuit assembly, first the cathode of the diode 3 is bonded to the mounting board 1', and the cathode of the diode 4 and the anode of the thyristor 5 are bonded to the mounting board 2' to respectively mount the diode 3, and the diode 4 and a thyristor 5 on the mounting boards 1' and 2'. Then the anode 3a of the diode 3 is connected to the anode 4a of the diode 4 with a lead wire 6 while the anode 4a of the diode 4 is connected to the cathode 5k of the thyristor 5 with a lead wire 7.
However, this conventional method is disadvantageous in that, since the connection of the lead wires 6 and 7 is effected with a wire bonder, the diameter of each of the lead wires 6 and 7 must be necessarily small, which results in the limitation of the current capacity. Furthermore, it is necessary to carry out the mounting of the diodes and the thyristor and the connection of the lead wires in separate processes, and in order to connect the lead wires to the diodes and the thyristor the bonding of the lead wires must be effected for every connection point. This increases the number of steps of manufacturing the assembly, which leads to an increment in manufacturing cost. This is another drawback accompanying the conventional method of manufacturing a hybrid integrated circuit assembly.